Automatic circuit breakers



April 16, 1957 P. M. cHRlsTl-:NSEN 2,789,179

AUTOMATIC CIRCUIT BREAKERS Filed April 1v. 1951 United States Patent O AUTOMATIC CIRCUIT BREAKERS Paul M. Christensen, West Orange, N. J., assignor to Federal Electric Products Company, Newark, N. J., a corporation of Delaware Application April 17, 1951, Serial No. 221,420

Claims. (Cl. 200-116) My present invention relates to automatic circuit breakers and more particularly to circuit breakers of the type in which an actuator is pivotally carried by the movable contact member and is latched thereto, under the control of a current-responsive device, for the manual operation of the circuit breaker to open and close it.

A circuit breaker of the general type to which the present invention relates is shown in Patent No. 2,209,352, issued on an application filed by me and Joseph Sachs, and is also shown in Patent No. Re. 23,188, issued on an application filed in the name of Harold A. Humpage, as well as by several pending applications assigned to the assignee of my present application, one or more of which applications will be subsequently referred to as the description proceeds.

As indicated by me and Joseph Sachs in said Patent No. 2,209,352 provision should be made for resiliently acting on the movable contact member for assuring the required contact pressure or proper engagement between the companion contacts of the circuit breaker when the breaker is closed, a resilient link indicated at 18 in said Patent No. 2,209,352, which connects the handle to the actuator, being provided for that purpose. Pursuant to the present invention it is unnecessary to provide a resilient link between the handle and the actuator for the movable contact member and it is also unnecessary to resiliently mount the contacts as disclosed in the Sachs application Ser. No. 152,020 referred to in said patent, which application issued as Patent No. 2,209,351 on July 30, 1940. The elimination of the requirement for a resilient link between the handle and the releasably latched switch actuator is obviated pursuant to my present invention whereby the connection between the handle and the actuator can be constituted by a rigid link, if desired, and yet a resilient mounting of the contacts is not required.

Pursuant to the present invention and an object thereof, a single spring is operable (1) to bias the movable contact member to open-circuit position and to move the movable contact member quickly to open-circuit position when the actuator is unlatched pursuant to the operation of the current-responsive latch device, (2) to resiliently oppose movement of the movable Contact member from circuit-open position to circuit-closed position7 (3) to resiliently hold the handle in the on position thereof when the circuit breaker is closed and to move the handle to its off position when the circuit breaker is tripped, and (4) to bias the movable contact member to resiliently press the movable contact against the stationary contact for proper Contact pressure when the circuit breaker is closed, to compensate for wear of the contact, or for other inequalities.

In conjunction with the above mentioned spring, the construction of the circuit breaker of the present invention is such that provision is made for limited bodily movement of the movable Contact member on a oating pivot to a limited extent to provide for the above mentioned action of the spring while the circuit breaker is closed, i. e., 'to provide the required resilient pressure between the companion contacts of the circuit breaker, to compensate for wear or other inequalities.

The above objects, features and advantages of the present invention will be fully understood, as will the invention itself, from the following description considered in connection with the accompanying illustrative drawings showing the presently preferred embodiment of this invention.

In the drawings:

Fig. 1 is a side view of a circuit breaker embodying the present invention, one of the casing parts being removed for the purpose of illustration, the circuit breaker mechanism being shown closed;

Fig. 2 is a view similar to Fig. 1 showing the circuit breaker mechanism open;

Fig. 3 is a sectional view on the line 3 3 of Fig. 1;

Fig. 4 is a sectional View on the line 4-4 of Fig. l;

Fig. 5 is an end view of the circuit breaker, both casing parts being in place; and

Figs. 6 and 7 are sectional views on the lines 6-6 and 7-7 respectively of Fig. 3.

Referring now to the drawings in detail the circuit breaker embodying lthe present invention comprises a two-part insulation casing having the complementary molded parts 10 and 12 in which the terminals 14 and 16, and the circuit breaker mechanism are mounted, as described for example in application Serial No. 127,433, led November 15, 1949, by Thomas M. Cole, now Patent No. 2,647,186 dated July 28, 1953, and in application Serial No. 217,162, filed March 23, 1951, by me and Thomas M. Cole, now Patent No. 2,642,509, dated J une 16, 1953. It will be understood that the two casing parts 10 and 12 are held together by bolts or other suitable means passing through openings 18 in casing part 10 and similar openings in casing part 12 which register with said opening 18 when the two casing parts are in assembled relation. While as here shown, the terminal member 16 is in the form of a prong of the plugin type as described in the above mentioned application Serial No. 127,433, it will be understood that this is not essential to the present invention but on the contrary a dilerent type of terminal member can be provided instead.

The stationary contact 20 is carried by the terminal member 14 in a position within the casing to be engaged by the movable contact 22 carried by the movable contact member 24. Said movable contact member is mounted for pivotal movement between the casing parts 10 and 12 to and from the circuit-closed position illustrated in Fig. 1, in which Contact 22 engages the stationary contact 20, and to and from the circuit-open position illustrated in Fig. 2 in which said movable contact 22 is shown disengaged from said stationary contact 20. This movement may be accomplished manually by the handle 26 which is connected to the channel-shaped actuator 28 by a U-shaped link 30 which is pivotally connected at one end thereof to said handle and at its opposite end to said actuator as will hereinafter be more specifically described. The actuator 28 is pivotally mounted on the movable contact member as indicated at 32 and is operatively connected to the movable contact member 24 for moving the latter, under the control of the current-responsive latch 34 which includes a bimetallic strip 36 and an electro magnet device 38, 40 by which said actuator 28 is releasably latched to the movable contact member 24 as described in the above mentioned application Serial No. 127,433. As described in the application Serial No. 217,162, tiled March 23, 1951, by me and Thomas M. Cole the pivot for the movable contact member may include the calibation device which comprises a screw 42 having a tapering part arsenaa- 44. and whichincludesthe nun 46.` The.. tapering part- 44 engages the movable contact member in an opening 48 adjacent to and laterally4 in communication with recessrfSOsintlre movable: contact member so .that b y. turne ing the'ziscrewr 42 inra clockwise direction, .viewing Fig. 1., part 24a of thei movable contactimemberzmaybemoved" or; displaced: im ai. counter-'eloclewise.v direction; (viewing Figs. l ar1d22.)`tY Withzrespect'to' the otlrerfpartiZdb ofthe: movable.: Contact; member. to which; the 1`atch device: 34l is. secured; wherebyY to provide: the* desired" degree of' overlap of; tb'epart 28kz1ob'th actuator: 28, thus.- to; predetermine the amount of exing thefbimetallic strip.' 36 in actuator-releasing direction, inresponse to. load cpnditiongeforctrippingr theircnit breaker;v Althougli'in thezillustratedembodiment; the :pivot: andf' calibration: de.L vicezeare found as a.ur1it,;thisf Vis-not` anressentialfeature of the present inventiorr andl the: pivot. and; calibration mayr be separate:v devices: as shown; for; examples in` the above mentioned application ofIThomas; M. Gole, Serial No. 127,433-.

ltwillbe understoodfthatiasrillustratechin Fig. l when the handle is'. ini. the: onr orl circuit-:closedl position thereof and the actuator 28 is1latched torth'el movable: conta'ct` member 24 byfengagementwith the; outer end' of the bimetallic strip 36, asshown, relativespivotal-move'- mentbetweerrtlreactuator: and thelmovable..contactmember isi'` prevented andi contact'` 22 isein engagement. with contactA 2,02. In this positionath'e link 36, whichV pursuant to*` therpresent",inventionl may-V` be azrigid-.linkg and the actuator 28', arerin oversetltoggle condition'and that in order forr the'circuitbreaker, to. openfeith'er automatically, i. e;, pursuantfto theiiexingof tliebimetalstripzeither upon heating thereofi or by the: attractionofmenrber 33lr to; the larmature :4U-fob the electromagnet, thetogglel mustv befbroken, andlthis-'can take place either byrmovement ofthe handle 26# to itsf cirouitopenposition (Fig. 2') manually orY by release'offtli'eendZSa of the actuator by tlrebi-metal strip' 363i wlienztlje circuit breaker trips -upon overload or otlrer; predeterminedi load"` conditions. Theopeningrof" the circuit breakerwhen-the latch 34vreleases the actuatorf`28`isfefected'by the spring 52wl1'icbis con nected at oneendtthereofto -tbeI handle towthe part 542 thereof and atits other'endto the-movable-contact member as-indicated at=5`6l- It will be observedthat said spring-is a-tension-spring andis connectedtothe movable contactl member so'as to biasf the latter to circuit-open position and to move the latter to said position when latch l-disengagesy actuator 28. Also it' will bel noted that. said-spring is eiective'tomove'f the handle 261toitsol or*- circuit-open. positionwhen thel circuitY breaker is-'r tripped, that islwhen the movable contact member moves to ray circuit-openposition pursuantl to the release ofactuator28`y by latch-3'4 Further it will be observedV that-e-ven though the handlevZt--` is held in on position, said springis-'efectveeto` open the circuit breakerl when theltter istripped;l i'.V e., when latch;34 disengages'actuator 285 AA feature ofthe-present" invention is-` thel provision-of the iloatir'rgpivot for the movable'contact member 24in conjunctionwith the spring-52-V for permitting a limited bodily movement'of themovablecontact memberVV and for biasing the movablecontact 22'- toward the stationary contact20, in the closedicircuitvpositionof said'movablev contact'l24 in order to provide the proper pressure be tween said2 contacts when' they areeerrgaged,`y or tocompensate` torY` wear orrother inequalities inthe various co operating partsrof 'thecircuit breaker. For this purpose, thebearingy part-58of pivot screw 42 and theV portion 60 of the4 companioncnut*46'have'limited movement-V in the bearing recesses- 62'L and 64, respectively, of casing parts12I andl 10,;respectively In thisconnectionvit will be obseryeditlia'tlbearinggrecesses 62 and 64# areelongated for' slidablefengagement; tofaf-liinited extent' bythe correspgiv'rrdiirgpartsl SSandat thepivot l'device in=avdirection transversely v"of thepivot-axis.l It willbe-notedtliat in the.. closed. conditionof. the, circuit breaker as. illustrated in Fig. 1, in which the movable contact member is restrained against pivotal movement, spring 52, being under tension, biases said movable contact member 24 for bodily movement toward the handle 26, that is in a direction to press movable contact. 22.. resiliently against the stationary contact 20. In this'connection it will be understood further. tli'atlwhilespring 52istl1'usieiective in this manner to press contact 22 against contact 20, itis also. potentially effective to move the movable contact member 24' pivotally to circuit-opening position the. instant latch 34 operates to disengage or release the actuator 28.

Referring.nowfmore-speciiically to handle 265-and link 30, it will be observed that said handle. 26is here shown in two parts 6o and 68 interlocked with each other, for unitary pivotal movement, by a projection on part 66 which ts into a recess 72 in part 68. The pivotal mounting. forA said handle comprisesithe..cylindrical;projections 7 41 and. 'I6-f on. the handle Y parts"Y which'.V are journaled"` in f bearing recesses '7,7fandf/'8rin-casing parts;v lll'andl', respectively. Inwillibe notedrthat the inner: handleportionsi4 Si). and 82 are spacedfromeachiother in confrontingrelation and that= the part 54 totwhichaspring 52-is connected". isaintegral. with handle:V portion 8@ andi projectsninto thespace betweenhandle portions.ctlLandZ-Lv Said. portionsv and-'b2` areV also provided withdnternal projectionsiA and186forming; pivotal bearings for the arms @Siand 9050i?` link 3) which connects the handle tov the actuator: 28; Saidlinkzalso'includes a cross member 92 which connects saidA arms 83` and 90 to each other,

and apivot pin 94pivotally connectsy arms 8S and 9@ toV the adjacent end of actuator 28.

Itlwillbe understood thativarious changes-in tliedetails ofi constructionv and inthe: arrangement of parts-may bemade: without departingV from the underlyin'gidea or principles of the presentiinvention within the scope of thel appended claims.

Having-thus described my invention, what l clainr and desiretok secure by Letters Patent'is:

1. Anautomatic circuitV breaker having a stationary contact, a movable-contact-member having-a contact en gageable with andi disengageable from said stationary contact, a current-responsivev latch-carried by` said movable contact member, pivotv means for said movable contact member, said pivot meansproviding for limited` bodilymovement of said movable contact` member, an actuator pivotally mounted on said contact memberl and operativelyA connected thereto, under controlrof saidllatch, fori closingV the circuit breaker, and a spring operable directlyonsaidmovable contact member to resilientlyurge. the contacts into engagement, wherebyto provide for proper contact pressure between said contacts in the' closed condition of the circuit breaker.

21 A circuitgbreaker comprising relatively movable companion contacts` engageabley withA and` disengageable from eachother forclosing and-opening the circuit' breaku er, a-.movable' memberv carrying one ofsaid contacts,

means forv actuating said movable member to Vengage and'- disengage saidcompanion contacts, said actuating means includinglatchingy means, and spring means for disen-l gaging'said contactsin'the unlatchedcondition thereof, meansprovidinga--floating-mounting on which said movable member` is` carried, andan' operative connection ofsaidspring meansv toy said movable member operable ini conjunction with said iioating mounting for exerting contact pressure betweenvsaidcompanion contacts in the en-l gaged condition thereof, a handle for manually operating.

saidA breaker and movable to on and otFpositions corresponding to the engaged anddisengaged conditions, respectively; of said contacts, and aconnectioni of said spring means to said handle formoving the latter. to itsA ott position concomitantly with the openingl of. the circuit breaker by said spring means.

31 A- circuit. breaker..` comprising; relatively movable cornpntnioi 1v contacts.. engageable; with and disengageable:

from each other for closing and opening the circuit breaker, a movable member carrying one of said contacts, means for actuating said movable member to engage and disengage said companion contacts, said actuating means including latching means, and spring means for disengaging said contacts in the unlatched condition thereof, means providing a floating mounting on which said movable member is carried, and an operative connection of said spring means to said movable member operable in conjunction with said floating mounting for exerting contact pressure between said companion contacts in the engaged condition thereof, a handle for manually operating said breaker and movable to on and olf positions corresponding to the engaged and disengaged conditions, respectively, of said contacts, and a toggle device connected to said movable member and operable by said handle to move said movable member to engage said contacts with each other and to hold them engaged in the latched condition of the breaker, said spring means being connected to said handle for operating the latter to hold the toggle links releasably in overset relation in the latched condition of the breaker, and said spring means being connected to said movable member between said toggle means and said foating mounting.

4. A circuit breaker comprising relatively movable contacts engageable with and disengageable from each other for making and breaking the circuit, a pivotally movable member carrying one of said contacts, a pivoted actuator and a current responsive latch carried by said movable member, said actuator being operable under the control of said latch to move said member to circuitclosing position, a pivoted handle having an operative rigid-member connection with said actuator to actuate the latter, and a tension spring connected at one end to said handle and at its other end to said movable member, said connection between said handle and said actuator including a link which forms a toggle with said actuator, said toggle being overset in the circuit making position of said movable contact-carrying member and said spring releasably holding said toggle in said overset condition when said actuator is latched to said movable member in said circuit making position thereof.

5. A circuit breaker comprising relatively movable contacts engageable with and disengageable from each other for making and breaking the circuit, a pivotally movable member carrying one of said contacts, a pivoted actuator and a current responsive latch carried by said movable member, said actuator being operable under the control of said latch to move said member to circuit-closing position, a pivoted handle having an operative rigid-member connection with said actuator to actuate the latter, and a tension spring connected at one end to said handle and at its other end to said movable member, said connection between said handle and said actuator including a link which forms a toggle with said actuator, said toggle being overset in the circuit making position of said movable contact-carrying member and said spring releasably holding said toggle in said overset condition when said actuator is latched to said movable member in said circuit making position thereof, said spring being operable to move said movable member and said handle to opencircuit positions when said actuator is released by said latch.

6. An automatic circuit breaker having a stationary contact, a movable contact member having a contact engageable with and disengageable from said stationary contact, a current-responsive latch carried by said movable contact member, pivot means for said movable contact member, said pivot means providing for limited bodily movement of said movable contact member, an actuator pivotally mounted on said contact member and operatively connected thereto, under control of said latch, for closing the circuit breaker, and a spring operable directly on said movable contact member between said pivot means and said actuator to resiliently urge the contacts into engagement, whereby to provide for proper contact pressure between said contacts in the closed condition of the circuit breaker.

7. A circuit breaker, including relatively removable companion contacts engageable with and disengageable from each other for closing and opening the circuit breaker, an elongated movable contact member carrying one of said contacts at one end thereof, said movable contact member having a loose pivotal mounting at a point spaced substantially from its ends and affording limited bodily movement thereof, current-responsive latching means, and actuating means for closing the circuit breaker under control of said latching means, said actuating means including a manual operating element and a rigid-member drive connection from said manual operating element to the end of said movable contact member remote from said one contact to drive the movable member in the contact-closing direction, and a spring directly engaging said movable contact member and arranged to be increasingly stressed during closing of the companion contacts and thus to store an increasing amount of spring energy during said closing operation and said spring being eiective to apply contact pressure, said spring acting to drive said movable contact member about said pivotal mounting upon release of said latching means to open said contacts and to return said rigid-member drive connection and said manual operating element to its circuit-breakeropen position.

8. A circuit breaker in accordance with claim 7 wherein said rigid-member drive connection is in the form of a toggle arranged to be over-set when the contacts have closed.

9. A circuit breaker comprising relatively movable companion contacts engageable with and disengageable from each other for closing and opening the circuit breaker, a movable member carrying one of said contacts and biased to effect separation of said contacts when the circuit breaker is conditioned to open, said movable member being provided with a floating pivotal mounting be-' tween the ends thereof, means for actuating said movableV member to engage and disengage said companion contacts, said movable member being provided with one of said contacts at one side of said pivotal mounting thereof, a rigid-member drive mechanism acting directly on said movable member at the other side of said pivotal mounting, and a spring acting directly on said movable member and cooperating with said drive mechanism for exerting contact pressure between said companion contacts in the engaged condition thereof, and trip means operable in response to predetermined current conditions to immediately relieve said contact pressure and to effect the opening of said circuit breaker.

l0. A circuit breaker comprising relatively movable contacts engageable with and disengageable from each other for making and breaking the circuit, a pivotally movable member carrying one of said contacts, and biased to effect separation thereof when the circuit breaker is conditioned to open, a pivoted actuator and a curent responsive latch carried by said movable member, a manual operating element having a rigid-member drive connection to said actuator, said actuator being operable under the control of said latch to move said member to circuit-closing position, and a spring acting directly on said movable contact member to provide contact pressure between said contacts in the engaged condition thereof. 1l. A circuit breaker comprising relatively movable contacts engageable with and disengageable from each other for making and breaking the circuit, a pivotally movable member carrying one of said contacts, and biased to effect separation thereof when the circuit breaker is conditioned to open, a pivoted actuator and a current responsive latch carried by said movable member, a manual operating element having a rigid-member drive connection to said actuator, said actuator being operable under the control of said latch to move said member to area-17e 7 circuit-closing position, and a spring acting directly on said movable contact member to provide contact pressure between saidccontacts in the engaged condition thereof, said spring being a tension spring and being operable to open the breaker in response to predetermined current condition.

l2. An automatic circuit breaker having a stationary contact, a pivotally movable contact member having a Contact engageable Vwith and disengageable from said stationary Contact, a current responsive latch carried by said movable contact member, and an actuator pivotally mounted on said contact member and operatively connected thereto, under the control of said latch, for closing vthe circuit breaker, a pivot on which `said movable contact member vis mounted for said pivotal movement thereof, means mounting said pivot for limited bodily movement, and spring means operable to eiiect a limited bodily movement of said movable contact member while said lactuator is latched thereto Vin a direction to resilient` ly urge said movable contact against said stationary con tact, whereby to provide for proper contact pressure be tween said Acontacts in the closed condition of the circuit breaker.

1'3. An rautomatic circuit breaker having a stationary Contact, a pivotally movable contact member having a contact engagea'ble with and disengageable from said sta tionary contact, a current responsive latch carried by said movable Contact member, and an actuator pivotally mounted on said contact member and operatively connected thereto, under the control of said latch, for closing the circuit breaker, a pivot on which said movable contact member is mounted for said pivotal movement thereof, means mounting said pivot for limited bodily movement, a manually operable handle movable to different positions for operating the movable `contact member to open and close the circuit breaker in the manual operation thereof, a connection between said handle and said actuator which prevents relative pivotal movement between said actuator and the movable contact member when the handle is in circuit-closing position and the actuator is latched to said movable contact member, and spring means operable to eifect a limited bodily movement of said movable contact member while said actuator is latched thereto in a direction to resiliently urge said movable contact against said stationary contact, whereby to provide for proper contact pressure between said contacts inthe closed condition of the circuit breaker.

14. An automatic circuit breaker having a stationary contact, a pivotally movable contact member having a contact engageable with and disengageable from said stationary contact, a current responsive latch carried by said movable contact member, and an actuator pivotally mounted on said contact member and operatively connected thereto, under the control of said latch, for closing the circuit breaker, a pivot -on which said movable contact member is mounted for said pivotal movement thereof, means mounting said pivot for limited bodily movement, a manually operable handle movable to different positions for operating the movable contact member to open and close the circuit breaker in the manual operation thereof, a connection between said handle and said actuator which prevents relative pivotal movement between said actuator and `the movable contact member when the handle is in circuit-closing position and the actuator is latched to said movable contact member, and spring means operable to effect a limited bodily movement of said movable contact member while said actuator is latched thereto in a direction to resiliently urge said movable contact against said stationary contact, whereby to provide for proper contact pressure between said contacts in the closed condition of the circuit breaker, said movable contact and said actuator being provided on said movable contact'member at opposite sides, respectively, of said pivot, and said spring means being operable on said movable contact member at one side of said pivot to 8V t move the movable contact member to circuit-open posi tion when said latch disengages said actuator'.

l5. An automatic circuit breaker having a stationary Contact, a pivotally movable contact member having a contact engageable -with and disengageable from said stationary Contact, a current responsive latch carried by said movable contact member, and an actuator pivotally mounted on said contact member and operatively connected thereto, u nder the control of said latch, for closing the circuit breaker, a pivot on which said movable contact member is mounted for said pivotal movement thereof, means mounting said pivot for limited bodily movement, a manually operable handle movable to different positions for operating the ymovable contact member to open and close the circuit breaker in the -manual operation thereof, a connection between said handle and said actuator which prevents relative pivotal movement between said actuator and the movable contact member when the handle is in circuit-closing position and the actuator is latched to said movable contact member, and spring means operable to effect a limited bodily movement of said movable contact member while said actuator is latched thereto in a direction to resiliently urge said movable contact against said stationary contact, whereby to provide for proper contact pressure between said contacts in the closed condition of the circuit breaker, said movable contact and said actuator being provided on said movable contact member at opposite sides, respectively, of said pivot', .and said spring means being operable on said movable contact member between said pivot and said actuator and operable on said handle to move the movable contact member and said handle to their respective circuit-open positions when said latch disengages said actuator.

16. YAn automatic circuit breaker having a stationary contact, a pivotally movable contact member having a contact engageable with and disengageablefrom said stationary contact, a current responsive latch carried by said movable contact member, and an actuator pivotally mounted on said contact member and operatively connected thereto, under the control of said latch, for closing the circuit breaker, a pivot member on which said movable contact member is mounted and bearing means for said pivot member ink which the latter has a limited movement transversely of the pivotal axis, and spring means operatively .connected to said movable contact member for biasing the same for movement transversely of said pivot in contact-engaging direction while the contacts are engaged in the latched condition of the circuit breaker.

17. A circuit breaker comprising relatively movable contacts engagcable with and disengageable from cach other for making and breaking the circuit, a pivotally movable member carrying one of said contacts, a pivoted actuator and a current responsive latch carried by said movable member, said actuator being operable lunder the control of said latch to move said member to circuitclosing position, a pivoted handle having an operative connection with said latch to actuate the latter, and a tension spring connected at one end to said handle and at its other end to said movable member between the pivotal axis thereof and said actuator, said connection between said handle and said actuator including a link which forms a toggle with said actuator, said toggle being over-set in the circuit making position of said movable contact-carrying member and said spring releasably holding said toggle in said overset condition when said actuator is latched to said movable member in said circuit making position thereof.

i8. A circuit breaker comprising a stationary contact, a pivotally movable member provided with a contact movable thereby for engagement Vwith and disengagement from said stationary contact, a manually operable handle movable to on and ott positions thereof, rigid-element means interconnecting said handle and said movable member for operation of said movable member by said handle to close said contacts in said on position of said handle and to move said movable member to a reset position in the oil position of said handle wherein said contacts are disengaged, current responsive means releasably latching said movable member in the circuit closed disposition thereof and operable upon predetermined current conditions to unlatch said movable member for disengaging said contacts, and spring means operable upon said unlatching of said movable member to open said circuit breaker, said spring means being a tension spring operatively interconnected between said handle and said movable member and effective in the closed position of said circuit breaker and after unlatching thereof to bias said movable member in a direction to disengage said contacts and to concomitantly bias said handle for movement to said ott position thereof.

19. A circuit breaker comprising a stationary contact, a pivotally movable member provi-ded with a contact movable thereby for engagement with and disengagement from said stationary Contact, a manually operable handle movable to on and oit positions thereof, rigid-element means interconnecting said handle and said movable member for operation of said movable member by said handle to close said contacts in said on position of said handle and to move said movable member to a reset position in the oi-f position of said handle wherein said contacts are disengaged, current responsive means releasably latching said movable member in the circuit closed disposition thereof and operable upon predeter mined current conditions to unlatch said movable member for disengaging said contacts, and spring means operable upon said unlatching of said movable member to open said circuit breaker, said spring means being a tension spring operatively interconnected between said handle and said movable member and effective in the closed position of said circuit breaker and after unlatching there- 10 of to bias said movable member in a direction to disengage said contacts and to concomitantly bias said handle for movement to said oi position thereof, one end of said tension spring being connected to said handle and the other end thereof being connected to said movable member.

20. A circuit breaker in accordance with claim 19, wherein said means interconnecting said handle and said movable member includes an actuator in latching engagement with said current responsive means when the circuit breaker is being closed and when it remains closed, said movable member together with said current responsive means and said actuator when latched being a triangular assembly movable with the movable contact member as a unit when the circuit breaker is being closed, and said tension spring providing bias for retaining said handle and said triangular assembly in the on position when latched.

References Cited in the le of this patent UNITED STATES PATENTS 1,925,422 Walsh Sept. 5, 1933 2,011,311 Gaynor Aug. 13, 1935 2,065,357 Von Hoorn Dec. 22, 1936 2,150,012 Von Hoorn Mar. 7, 1939 2,184,372 Von Hoorn Dec. 26, 1939 2,209,319 Christensen July 30, 1940 2,209,351 Sachs July 30, 1940 2,288,081 Frank June 30, 1942 2,290,495 Sandin et al. July 21, 1942 2,416,266 Landmeier Feb. 18, 1947 2,459,427 Humpage Ian. 18, 1949 2,642,509 Cole et al. June 16, 1953 2,647,186 Cole July 28, 1953 2,660,637 Thomas Nov. 24, 1953 

